Sink



FIG. 1 is a perspective view of a sink showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a side view thereof; and

FIG. 4 is a side view thereof, opposite that of FIG. 3; and,

FIG. 5 is a top view thereof.

The broken lines in the drawings illustrate portions of the sink that form no part of the claimed design. 

CLAIM The ornamental design for a sink, as shown and described. 